Inflammasomes are multiprotein complexes, which assembly results in caspase-1 activation and subsequent IL-1β and IL-18 activation and secretion. In a cell-free system, based on cytosols of normally growing cells, the disruption of the cell membrane spontaneously activates the inflammasome. Studying the activation of the inflammasome in cytosolic extracts provides multiple advantages, as it is synchronized, rapid, strong, and mostly plasma membrane-free. This protocol covers the methods required to prepare cell lysates and study inflammasome activation using different read-outs. General considerations are provided that may help in the design of modified methods. This assay can be useful to study potential inflammasome interactors and the signaling pathways involved in its activation.